Name: discovery of metastatic regulators using a rapid and quantitative intravital chick chorioallantoic membrane model
Uploaded: 2021-02-03T13:30:00
Description: Watch this Scientific Journal Video about Discovery of Metastatic Regulators using a Rapid and Quantitative Intravital Chick Chorioallantoic Membrane Model at JoVE.com

This work was supported by Canadian Cancer Society Research Institute Grant #702849 to JDL and KS. Dr. Lewis holds the Frank and Carla Sojonky Chair in Prostate Cancer Research supported by the Alberta Cancer Foundation.

All experiments were performed in accordance with the regulations and guidelines of the Institutional Animal Care and Use Committee at the University of Alberta. Avian embryos are not considered to be live animals by many research institutes and no animal protocols are required. It is, however, an accepted view that avian embryos can feel pain and, therefore, must be treated as humanely as possible. The local animal research authority must be contacted prior commencing of any research work to ensure that proper regulatio...

<ol>
	<li>Hanahan, D., Weinberg, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hallmarks+of+cancer:+The+next+generation.">Hallmarks of cancer: The next generation.</a> Cell. 144 (5), 646-674 (2011).</li><li>Van't Veer, L. J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Gene+expression+profiling+predicts+clinical+outcome+of+breast+cancer.">Gene expression profiling predicts clinical outcome of breast cancer.</a> Nature. 415 (6871), 530-536 (2002).</li><li>Eccles, S. A., Welch, D. 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J., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tumor+cell-driven+extracellular+matrix+remodeling+drives+haptotaxis+during+metastatic+progression.">Tumor cell-driven extracellular matrix remodeling drives haptotaxis during metastatic progression.</a> Cancer Discovery. 6 (5), 516-531 (2016).</li><li>Leong, H. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Intravital+imaging+of+embryonic+and+tumor+neovasculature+using+viral+nanoparticles.">Intravital imaging of embryonic and tumor neovasculature using viral nanoparticles.</a> Nature Protocols. 5 (8), 1406-1417 (2010).</li><li>Kain, K. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+chick+embryo+as+an+expanding+experimental+model+for+cancer+and+cardiovascular+research.">The chick embryo as an expanding experimental model for cancer and cardiovascular research.</a> Developmental Dynamics : An official Publication of the American Association of Anatomists. 243 (2), 216-228 (2014).</li><li>Zijlstra, A., Lewis, J., Degryse, B., Stuhlmann, H., Quigley, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+inhibition+of+tumor+cell+intravasation+and+subsequent+metastasis+via+regulation+of+in+vivo+tumor+cell+motility+by+the+tetraspanin+CD151.">The inhibition of tumor cell intravasation and subsequent metastasis via regulation of in vivo tumor cell motility by the tetraspanin CD151.</a> Cancer Cell. 13 (3), 221-234 (2008).</li><li>Palmer, T. D., Lewis, J., Zijlstra, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+analysis+of+cancer+metastasis+using+an+avian+embryo+model.">Quantitative analysis of cancer metastasis using an avian embryo model.</a> Journal of visualized experiments : JoVE. (51), e2815 (2011).</li><li>Stoletov, K., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Quantitative+in+vivo+whole+genome+motility+screen+reveals+novel+therapeutic+targets+to+block+cancer+metastasis.">Quantitative in vivo whole genome motility screen reveals novel therapeutic targets to block cancer metastasis.</a> Nature Communications. 9 (1), 2343 (2018).</li><li>Leong, H. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Invadopodia+are+required+for+cancer+cell+extravasation+and+are+a+therapeutic+target+for+metastasis.">Invadopodia are required for cancer cell extravasation and are a therapeutic target for metastasis.</a> Cell Reports. 8 (5), 1558-1570 (2014).</li><li>Willetts, L., Bond, D., Stoletov, K., Lewis, J. 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Here we describe a rapid fluorescence microscopy based intravital screening protocol that can be utilized for important applications such as genetic or drug candidate screens. Cancer cells that have been transduced with a genetic library of interest or transfected with individual expression constructs can be rapidly screened and quantified as to phenotype of interest using this chick CAM model. Since transduction or transfection protocols vary significantly, depending on the library type, they are not included in this pr...

Metastasis is the main cause of cancer patient death1,2,3. Metastatic cancer cells utilize distinct signaling pathways, dependent on the type of cancer, throughout the five steps of the metastatic cascade: local invasion, intravasation, survival in the circulation, extravasation, and colony expansion at distant metastatic sites. Current understanding of this metastatic process suggests that there are two bottleneck steps, one is directional invasion of the cancer cell from the primary tumor, and the second is the establishment of the distant site metastatic lesion4,5,6. Both steps require cancer cells to actively interact with collagen and vasculature at the sites of initial invasion or distant metastatic lesion formation. Therefore, metastatic cancer cells must be able to attach to cells, remodel collagen fibers, and directionally invade along vascular walls7. Screening models that can rapidly identify antimetastatic therapeutic targets to block cancer cells from completing these steps is of the highest importance. Existing in vitro screening models do not fully mimic the complex live tissue environment. Mouse models are costly and time consuming. Therefore, there is an urgent need for intravital screening platforms that provide complex live tissue environments and rapid identification of targets.
Within the last decade, the chicken embryo has been established as a robust and cost-effective model of human cancer metastasis8,9,10,11,12. The chick chorioallantoic membrane (CAM) tissue is thin and translucent which makes it ideal for intravital microscopic imaging of cell and colony behaviors in primary tumor and/or metastatic sites12. Primary tumor growth from multiple human cancer cell lines can be initiated and metastasized within a span of only several days after microinjection into the CAM tissue. Cancer cells can be administered into the CAM tissue in several ways, including intravenously, intra-CAM or as collagen onplants, this flexibility allows the researcher to focus on specific stages of cancer progression, for example, metastatic lesion formation, invasion out of the primary tumor or angiogenesis.
Here we describe a quantitative screening platform that can be used to measure the ability of cancer cells to establish invasive metastatic lesions. Cancer cells that have been transduced with an expression library are injected intravenously into the CAM vasculature at low density. Metastatic colonies form for 4-5 days, then the invasion capacity and vasculature interaction of the resulting colonies is evaluated. Individual colonies that fail to invade are excised, propagated and their phenotype is confirmed in the CAM by reinjection and quantification of colony compactness and cancer cell-blood vessel contacts. The expression library constructs responsible for the single metastatic colony mutant phenotype are identified from isolated colony genomic DNA via high throughput sequencing. The same platform may be further used to validate the causal link between a gene and the observed phenotype or to perform in-depth mechanistic studies on the observed phenotype.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>1 mL disposable syringes</td>
			<td>BD</td>
			<td>BD309659</td>
			<td></td>
		</tr>
		<tr>
			<td>15 mL conical centrifuge tubes.</td>
			<td>Corning</td>
			<td>CLS430791-500EA</td>
			<td></td>
		</tr>
		<tr>
			<td>18 gauge x 1 1/2&#160; BD precision needle</td>
			<td>BD</td>
			<td>BD305196</td>
			<td>we use 1.2mm x 40mm, it is possible to use shorter needles if preferred</td>
		</tr>
		<tr>
			<td>2.5% Trypsin solution</td>
			<td>many sources are available</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>4T1 mouse breast cancer</td>
			<td>ATCC</td>
			<td>CRL-2539</td>
			<td></td>
		</tr>
		<tr>
			<td>B16F10 mouse melanoma cell line</td>
			<td>ATCC</td>
			<td>CRL-6475</td>
			<td></td>
		</tr>
		<tr>
			<td>Benchtop centrifuge.</td>
			<td>many sources are available</td>
			<td></td>
			<td>Any TC compatible centrifuge that can be used to spin down the cells is suitable</td>
		</tr>
		<tr>
			<td>Circular coverslips, 22 mm.</td>
			<td>Fisher Scientific</td>
			<td>12-545-101</td>
			<td></td>
		</tr>
		<tr>
			<td>Collagenase</td>
			<td>Sigma</td>
			<td>C0130-100MG</td>
			<td></td>
		</tr>
		<tr>
			<td>Confocal microscope</td>
			<td></td>
			<td></td>
			<td>We use Nikon A1r</td>
		</tr>
		<tr>
			<td>cotton swabs</td>
			<td>many sources are available</td>
			<td></td>
			<td>must be sterilized before use</td>
		</tr>
		<tr>
			<td>Culture media appropriate for the cell lines used</td>
			<td>many sources are available</td>
			<td></td>
			<td>We grow HT1080, HEp3 and b16 cell lines in DMEM, 10% FBS media</td>
		</tr>
		<tr>
			<td>Egg incubator</td>
			<td>many sources are available</td>
			<td></td>
			<td>An exact model that is necessary depends on the scale of the screen. Available sources are MGF Company Inc., Savannah, GA, or&#160; Lyon Electric Company Inc., Chula Vista, CA</td>
		</tr>
		<tr>
			<td>eppendor tubes , 1.5ml</td>
			<td>Sigma</td>
			<td>T4816-250EA</td>
			<td></td>
		</tr>
		<tr>
			<td>Fertilized White Leghorn eggs</td>
			<td>any local supplyer</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>fine forceps</td>
			<td>many sources are available</td>
			<td></td>
			<td>must be sterilized begfore use</td>
		</tr>
		<tr>
			<td>Hemocytometer&#160;</td>
			<td>Millipore-Sigma</td>
			<td>MDH-4N1-50PK</td>
			<td></td>
		</tr>
		<tr>
			<td>HT1080 human fibrosarcoma cell line</td>
			<td>ATCC</td>
			<td>CCL-121</td>
			<td></td>
		</tr>
		<tr>
			<td>Image analysis software</td>
			<td></td>
			<td></td>
			<td>We use Nikon Elements</td>
		</tr>
		<tr>
			<td>Lectin Lens Culinary Agglutinin (LCA) conjugated with Fluorescein or Rhodamine&#160;</td>
			<td>Vector Laboratories</td>
			<td>RL-1042, FL-1041</td>
			<td>Dilute stock (5mg/ml) 50-100x depending on the microscope sensetivity. Must be a different color from the color of cell line used for screening</td>
		</tr>
		<tr>
			<td>MDA-MB-468 human breast cancer</td>
			<td>ATCC</td>
			<td>HTB-132</td>
			<td></td>
		</tr>
		<tr>
			<td>PBS (1x)</td>
			<td>many sources are available</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Plastic weighting dishes&#160;</td>
			<td>Simport</td>
			<td>CA11006-614</td>
			<td>dimensions are 78x78x25mm; many other sources are available</td>
		</tr>
		<tr>
			<td>small surgical scissors&#160;</td>
			<td>many sources are available</td>
			<td></td>
			<td>must be sterilized before use</td>
		</tr>
		<tr>
			<td>Sodium borosilicate glass capillary tubes, outer diameter 1.0 mm, inner diameter 0.58 mm, 10 cm length&#160;</td>
			<td>Sutter Instrument</td>
			<td>BF100-58-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Square petri dishes (used as lids for the weighting dishes).</td>
			<td>&#160;VWR&#160;</td>
			<td>CA25378-115&#160;</td>
			<td>dimensions are 100x100x15mm; many other sources are available</td>
		</tr>
		<tr>
			<td>Stereo fluorescent microscope&#160;</td>
			<td></td>
			<td></td>
			<td>We use Zeiss Lumar v12</td>
		</tr>
		<tr>
			<td>Tygon R-3603 laboratory tubing</td>
			<td>Cole-Parmer</td>
			<td>AAC00001</td>
			<td>1/32 in inner diameter, 3/32 in. outer diameter, 1/32 in. wall thickness</td>
		</tr>
		<tr>
			<td>U-118 MG human glioblastoma</td>
			<td>ATCC</td>
			<td>HTB-15</td>
			<td></td>
		</tr>
		<tr>
			<td>U-87 MG human glioblastoma</td>
			<td>ATCC</td>
			<td>HTB-14</td>
			<td></td>
		</tr>
		<tr>
			<td>Vertical pipette puller&#160;</td>
			<td>many sources are available</td>
			<td></td>
			<td>we use David Kopf Instruments, Tujunga, CA; Model 720</td>
		</tr>
	</tbody>
</table>

discovery of metastatic regulators using a rapid and quantitative intravital chick chorioallantoic membrane model

Recent advances in cancer research has illustrated the highly complex nature of cancer metastasis. Multiple genes or genes networks have been found to be involved in differentially regulating cancer metastatic cascade genes and gene products dependent on the cancer type, tissue, and individual patient characteristics. These represent potentially important targets for genetic therapeutics and personalized medicine approaches. The development of rapid screening platforms is essential for the identification of these genetic targets.
The chick chorioallantoic membrane (CAM) is a highly vascularized, collagen rich membrane located under the eggshell that allows for gas exchange in the developing embryo. Due to the location and vascularization of the CAM, we developed it as an intravital human cancer metastasis model that allows for robust human cancer cell xenografting and real-time imaging of cancer cell interactions with the collagen rich matrix and vasculature. 
Using this model, a quantitative screening platform was designed for the identification of novel drivers or suppressors of cancer metastasis. We transduced a pool of head and neck HEp3 cancer cells with a complete human genome shRNA gene library, then injected the cells, at low density, into the CAM vasculature. The cells proliferated and formed single-tumor cell colonies. Individual colonies that were unable to invade into the CAM tissue were visible as a compact colony phenotype and excised for identification of the transduced shRNA present in the cells. Images of individual colonies were evaluated for their invasiveness. Multiple rounds of selections were performed to decreases the rate of false positives. Individual, isolated cancer cell clones or newly engineered clones that express genes of interest were subjected to primary tumor formation assay or cancer cell vasculature co-option analysis. In summary we present a rapid screening platform that allows for anti-metastatic target identification and intravital analysis of a dynamic and complex cascade of events.

Cancer cell injection is considered to be successful if the majority of the cells that are lodged in the capillaries are single and located at a significant difference from each other (~0.05-0.1 cm) so the colonies will not overlap after 5-6 days of incubation period (Figure 3A). The injection was not successful if a buildup of cancer cells can be seen in most of capillaries, embryos displaying this should be discarded (Figure 2E...

Watch this Scientific Journal Video about Discovery of Metastatic Regulators using a Rapid and Quantitative Intravital Chick Chorioallantoic Membrane Model at JoVE.com

Discovery of Metastatic Regulators using a Rapid and Quantitative Intravital Chick Chorioallantoic Membrane Model

This is an effective method to screen for suppressors or drivers of cancer metastasis. Cells, transduced with an expression library, are injected into the chicken chorioallantoic membrane vasculature to form metastatic colonies. Colonies having decreased or increased invasiveness are excised, expanded, reinjected to confirm their phenotype, and finally, analyzed using high throughput sequencing.

Recent advances in cancer research has illustrated the highly complex nature of cancer metastasis. Multiple genes or genes networks have been found to be ...

Our protocol permits an efficient identification of gene or gene combinations that block cancer invasion in viewer. over culture does not require advanced animal facilities for maintenance. As a whole, as a generic or general special libraries can be screened in a matter of several weeks in viewer.This over screening system will help researchers discover novel therapeutic gene targets or gene targets combinations that it can be used to block cancer metastasis. For IV injection, concentrate cells to 0.5 to 1 million cells per milliliter, using ice cold 1X PBS to dilute or re-suspend the cells. Expect approximately one milliliter of cell suspension will be needed for every 10 embryos.To assemble the injection apparatus, mount a needle onto the syringe, and then extend the syringe needle with a three to five centimeter long piece of tubing. Break the tip of the borosilicate needle using fine forceps. Load the syringe with 50 to 200 microliters of the cancer cell suspension.And insert the borosilicate needle into the tubing. Inspect the needle for cell clogging and air bubbles. If cell clogging is observed within the capillary, remove the capillary, re-suspend the cells and replace it with a new capillary.Use the plunger to push out any bubbles. Remove the cover lid and transfer the embryo under the stereoscope. Identify the appropriate vein to be injected on the CAM surface;which is normally only slightly wider than the diameter of the borosilicate needle tip and located midway between the embryo and the weighing dish wall.It is generally easier to inject at the point immediately adjacent to the vein bifurcation. Press the tip of the needle against the blood vessel wall and apply gentle pressure in the same direction as the blood flow. If necessary, use a cotton swab to help anchor or stabilize the vessel that is being injected.Gently depress the syringe plunger for 2 to 10 seconds until the desired volume is injected. Discard the embryo if excessive bleeding or clear liquid accumulation appears at the injection site. Remove the needle from the CAM and gently dab the injection site with a cotton swab to remove any blood or excess cancer cells.Cover the injected embryo in the weighing dish with the lid and return it to the incubator. Repeat the procedure until all embryos are injected. Visually inspect the embryos for bacteria or mold contamination or death.And discard contaminated embryos according to laboratory disposal procedures. Ensure that metastatic colonies appear uniform in shape during the first one to three days post-injection. And identify invasive or noninvasive metastatic colonies at days four to five post-injection.At day five post-injection, remove the embryos from the incubator and inspect and locate the embryo CAMs for metastatic colony distribution. Under the dissection microscope, gently pull the CAM tissue that contains the metastatic colony of interest upwards using fine forceps, and cut it off with surgical scissors. Transfer the CAM tissue into an empty, sterile 1.5 milliliter tube and close the tube lid.Repeat the excision procedure until all the colonies of interest are collected into separate tubes. Gently mince the CAM tissue in a micro centrifuge tube, using a separate sterile 18 gauge needle for each colony. Add 100 microliters of 1X collagen-A solution and incubate for 30 minutes at 37 degrees Celsius.Spin down the cells and CAM tissue at 300 times G for five minutes at ambient temperature. Aspirate the collagen-A solution and re-suspend the cells incomplete media for the cell line of interest. Then spin the cells and tissue again.Re-suspend cells and tissue pieces in one milliliter of complete media and selection factor, if any. Then transfer into a single 12-well tissue culture dish well. For the next one to three weeks, monitor the cancer cells daily for growth and contamination.When the cells reach 70 to 80%of confluency transfer them into a larger volume culture dish. Proceed to sequencing or the next round of selection, as soon as adequate cancer cell numbers are reached. Embryos displaying a buildup of cancer cells due to unsuccessful injection, can be seen in most of the capillaries.When the optimal cell concentration and duration of injection is achieved, day five post-injection transduced cells should produce a wide variety of colony phenotypes, with the majority of the colonies invasive as determined by the cancer cells appearing scattered in the CAM tissue. Attention should be paid to the metastatic colonies that appear compact and are located far enough from neighboring colonies that they can be excised with forceps and scissors and one piece of CAM tissue. An isolated positive screen hit should display the compact colony phenotype upon re-injection.For measurement of the cancer cell blood vessel contacts, attention should be paid to the vascular wall stain brightness and the appropriate amount of lectins should be injected for the vascular wall signal. When attempting this protocol avoid under or over injection and remove excessive bleeding or liquid buildup. Several novel genes that are driving cancer cell invasion in viewer have been identified using this technique.

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Research

JoVE Journal

Cancer Research

Advanced Animal Model of Colorectal Metastasis in Liver: Imaging Techniques and Properties of Metastatic Clones

Patients with a limited number of hepatic metastases and slow rates of progression can be successfully treated with local treatment approaches1,2. However, little is known about the heterogeneity of liver metastases, and animal models capable of evaluating the development of individual metastatic colonies are needed. Here, we present an advanced model of hepatic metastases that provides the ability to quantitatively visualize the development of individual tumor clones in the liver and estimate their growth kinetics and colonization efficiency. We generated a panel of monoclonal derivatives of HCT116 human colorectal cancer cells stably labeled with luciferase and tdTomato and possessing different growth properties. With a splenic injection followed by a splenectomy, the majority of these clones are able to generate hepatic metastases, but with different frequencies of colonization and varying growth rates. Using the In Vivo&#160;Imaging System (IVIS), it is possible to visualize and quantify metastasis development with in vivo luminescent and ex vivo fluorescent imaging. In addition, Diffuse Luminescent Imaging Tomography (DLIT) provides a 3D distribution of liver metastases in vivo. Ex vivo fluorescent imaging of harvested livers provides quantitative measurements of individual hepatic metastatic colonies, allowing for the evaluation of the frequency of liver colonization and the growth kinetics of metastases. Since the model is similar to clinically observed liver metastases, it can serve as a modality for detecting genes associated with liver metastasis and for testing potential ablative or adjuvant treatments for liver metastatic disease.

The ability of metastatic clones to colonize distant sites depends on their proliferation capacity and/or their ability to survive in the host microenvironment without significant proliferation. Here, we present an animal model that allows quantitative visualization of both types of liver colonization by metastatic clones.

Patients with a limited number of hepatic metastases and slow rates of progression can be successfully treated with local treatment approaches1,2. ...

A Syngeneic Mouse Model of Metastatic Renal Cell Carcinoma for Quantitative and Longitudinal Assessment of Preclinical Therapies

Renal cell carcinoma (RCC) affects &#62; 60,000 people in the United States annually, and ~ 30% of RCC patients have multiple metastases at the time of diagnosis. Metastatic RCC (mRCC) is incurable, with a median survival time of only 18 months. Immune-based interventions (e.g., interferon (IFN) and interleukin (IL)-2) induce durable responses in a fraction of mRCC patients, and multikinase inhibitors (e.g., sunitinib or sorafenib) or anti-VEGF receptor monoclonal antibodies (mAb) are largely palliative, as complete remissions are rare. Such shortcomings in current therapies for mRCC patients provide the rationale for the development of novel treatment protocols. A key component in the preclinical testing of new therapies for mRCC is a suitable animal model. Beneficial features that recapitulate the human condition include a primary renal tumor, renal tumor metastases, and an intact immune system to investigate any therapy-driven immune effector responses and the formation of tumor-induced immunosuppressive factors. This report describes an orthotopic mRCC mouse model that has all of these features. We describe an intrarenal implantation technique using the mouse renal adenocarcinoma cell line Renca, followed by the assessment of tumor growth in the kidney (primary site) and lungs (metastatic site).

Implementation of an orthotopic model of renal cell carcinoma in immunocompetent mice affords the investigator a clinically-relevant system defined by the presence of a primary renal tumor and lung metastases in the same animal. This system can be used to preclinically test a variety of treatments in vivo.

Renal cell carcinoma (RCC) affects &#62; 60,000 people in the United States annually, and ~ 30% of RCC patients have multiple metastases at the time of ...

Murine Model of Metastatic Liver Tumors in the Setting of Ischemia Reperfusion Injury

Liver ischemia and reperfusion (I/R) injury, a common clinical challenge, remains an inevitable pathophysiological process that has been shown to induce multiple tissue and organ damage. Despite recent advances and therapeutic approaches, the overall morbidity has remained unsatisfactory especially in patients with underlying parenchymal abnormalities. In the context of aggressive cancer growth and metastasis, surgical I/R is suspected to be the promoter regulating tumor recurrence. This article aims to describe a clinically relevant murine model of liver I/R and colorectal liver metastasis. In doing so, we aim to assist other investigators in establishing and perfecting this model for their routine research practice to better understand the effects of liver I/R on promoting liver metastases.

We describe in detail a clinically relevant colorectal cancer liver metastases (CRLM) tumor model and the influence of liver ischemia reperfusion (I/R) in tumor growth and metastasis. This model can help to better understand the mechanisms underlying surgery-induced promotion of liver metastatic growth.

Liver ischemia and reperfusion (I/R) injury, a common clinical challenge, remains an inevitable pathophysiological process that has been shown to induce ...

Comparing Metastatic Clear Cell Renal Cell Carcinoma Model Established in Mouse Kidney and on Chicken Chorioallantoic Membrane

Metastatic clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer. Localized ccRCC has a favorable surgical outcome. However, one third of ccRCC patients will develop metastases to the lung, which is related to a very poor outcome for patients. Unfortunately, no therapy is available for this deadly stage, because the molecular mechanism of metastasis remains unknown. It has been known for 25 years that the loss of function of the von Hippel-Lindau (VHL) tumor suppressor gene is pathognomonic of ccRCC. However, no clinically relevant transgenic mouse model of ccRCC has been generated. The purpose of this protocol is to introduce and compare two newly established animal models for metastatic ccRCC. The first is renal implantation in the mouse model. In our laboratory, the CRISPR gene editing system was utilized to knock out the VHL gene in several RCC cell lines. Orthotopic implantation of heterogeneous ccRCC populations to the renal capsule created novel ccRCC models that develop robust lung metastases in immunocompetent mice. The second model is the chicken chorioallantoic membrane (CAM) system. In comparison to the mouse model, this model is more time, labor, and cost-efficient. This model also supported robust tumor formation and intravasation. Due to the short 10 day period of tumor growth in CAM, no overt metastasis was observed by immunohistochemistry (IHC) in the collected embryo tissues. However, when tumor growth was extended by two weeks in the hatched chicken, micrometastatic ccRCC lesions were observed by IHC in the lungs. These two novel preclinical models will be useful to further study the molecular mechanism behind metastasis, as well as to establish new, patient-derived xenografts (PDXs) toward the development of novel treatments for metastatic ccRCC.

Metastatic clear cell renal cell carcinoma is a disease without a comprehensive animal model for thorough preclinical investigation. This protocol illustrates two novel animal models for the disease: the orthotopically implanted mouse model and the chicken chorioallantoic membrane model, both of which demonstrate lung metastasis resembling clinical cases.

Metastatic clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer. Localized ccRCC has a favorable surgical outcome. However, ...

Identification of Transcription Factor Regulators using Medium-Throughput Screening of Arrayed Libraries and a Dual-Luciferase-Based Reporter

Transcription factors can alter the expression of numerous target genes that influence a variety of downstream processes making them good targets for anti-cancer therapies. However, directly targeting transcription factors is often difficult and can cause adverse side effects if the transcription factor is necessary in one or more adult tissues. Identifying upstream regulators that aberrantly activate transcription factors in cancer cells offers a more feasible alternative, particularly if these proteins are easy to drug. Here, we describe a protocol that can be used to combine arrayed medium-scale lentiviral libraries and a dual-luciferase-based transcriptional reporter assay to identify novel regulators of transcription factors in cancer cells. Our approach offers a quick, easy, and inexpensive way to test hundreds of genes in a single experiment. To demonstrate the use of this approach, we performed a screen of an arrayed lentiviral RNAi library containing several regulators of Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ), two transcriptional co-activators that are the downstream effectors of the Hippo pathway. However, this approach could be modified to screen for regulators of virtually any transcription factor or co-factor and could also be used to screen CRISPR/CAS9, cDNA, or ORF libraries.

To identify novel regulators of transcription factors, we developed an approach to screen arrayed lentiviral or retroviral RNAi libraries using a dual-luciferase-based transcriptional reporter assay. This approach offers a quick and relatively inexpensive way to screen hundreds of candidates in a single experiment.

Transcription factors can alter the expression of numerous target genes that influence a variety of downstream processes making them good targets for ...

Using the Chicken Chorioallantoic Membrane In Vivo Model to Study Gynecological and Urological Cancers

Mouse models are the benchmark tests for in vivo cancer studies. However, cost, time, and ethical considerations have led to calls for alternative in vivo cancer models. The chicken chorioallantoic membrane (CAM) model provides an inexpensive, rapid alternative that permits direct visualization of tumor development and is suitable for in vivo imaging. As such, we sought to develop an optimized protocol for engrafting gynecological and urological tumors into this model, which we present here. Approximately 7 days postfertilization, the air cell is moved to the vascularized side of the egg, where an opening is created in the shell. Tumors from murine and human cell lines and primary tissues can then be engrafted. These are typically seeded in a mixture of extracellular matrix and medium to avoid cellular dispersal and provide nutrient support until the cells recruit a vascular supply. Tumors may then grow for up to an additional 14 days prior to the eggs hatching. By implanting cells stably transduced with firefly luciferase, bioluminescence imaging can be used for the sensitive detection of tumor growth on the membrane and cancer cell spread throughout the embryo. This model can potentially be used to study tumorigenicity, invasion, metastasis, and therapeutic effectiveness. The chicken CAM model requires significantly less time and financial resources compared to traditional murine models. Because the eggs are immunocompromised and immune tolerant, tissues from any organism can potentially be implanted without costly transgenic animals (e.g., mice) required for implantation of human tissues. However, many of the advantages of this model could potentially also be limitations, including the short tumor generation time and immunocompromised/immune tolerant status. Additionally, although all tumor types presented here engraft in the chicken chorioallantoic membrane model, they do so with varying degrees of tumor growth.

We present the chicken chorioallantoic membrane model as an alternative, transplantable, in vivo model for the engraftment of gynecological and urological cancer cell lines and patient-derived tumors.

Mouse models are the benchmark tests for in vivo cancer studies. However, cost, time, and ethical considerations have led to calls for alternative in vivo ...

A Novel Stromal Fibroblast-Modulated 3D Tumor Spheroid Model for Studying Tumor-Stroma Interaction and Drug Discovery

Tumor-stroma interactions play an important role in cancer progression. Three-dimensional (3D) tumor spheroid models are the most widely used in vitro model in the study of cancer stem/initiating cells, preclinical cancer research, and drug screening. The 3D spheroid models are superior to conventional tumor cell culture and reproduce some important characters of real solid tumors. However, conventional 3D tumor spheroids are made up exclusively of tumor cells. They lack the participation of tumor stromal cells and have insufficient extracellular matrix (ECM) deposition, thus only partially mimicking the in vivo conditions of tumor tissues. We established a new multicellular 3D spheroid model composed of tumor cells and stromal fibroblasts that better mimics the in vivo heterogeneous tumor microenvironment and its native desmoplasia. The formation of spheroids is strictly regulated by the tumor stromal fibroblasts and is determined by the activity of certain crucial intracellular signaling pathways (e.g., Notch signaling) in stromal fibroblasts. In this article, we present the techniques for coculture of tumor cells-stromal fibroblasts, time-lapse imaging to visualize cell-cell interactions, and confocal microscopy to display the 3D architectural features of the spheroids. We also show two examples of the practical application of this 3D spheroid model. This novel multicellular 3D spheroid model offers a useful platform for studying tumor-stroma interaction, elucidating how stromal fibroblasts regulate cancer stem/initiating cells, which determine tumor progression and aggressiveness, and exploring involvement of stromal reaction in cancer drug sensitivity and resistance. This platform can also be a pertinent in vitro model for drug discovery.

A novel three-dimensional spheroid model based on the heterotypic interaction of tumor cells and stromal fibroblasts is established. Here, we present coculture of tumor cells and stromal fibroblasts, time-lapse imaging, and confocal microscopy to visualize the formation of spheroids. This three-dimensional model offers a pertinent platform to study tumor-stroma interactions and test cancer therapeutics.

Tumor-stroma interactions play an important role in cancer progression. Three-dimensional (3D) tumor spheroid models are the most widely used in vitro ...

Quantifying the Brain Metastatic Tumor Micro-Environment using an Organ-On-A Chip 3D Model, Machine Learning, and Confocal Tomography

Brain metastases are the most lethal cancer lesions; 10-30% of all cancers metastasize to the brain, with a median survival of only ~5-20 months, depending on the cancer type. To reduce the brain metastatic tumor burden, gaps in basic and translational knowledge need to be addressed. Major challenges include a paucity of reproducible preclinical models and associated tools. Three-dimensional models of brain metastasis can yield the relevant molecular and phenotypic data used to address these needs when combined with dedicated analysis tools. Moreover, compared to murine models, organ-on-a-chip models of patient tumor cells traversing the blood brain barrier into the brain microenvironment generate results rapidly and are more interpretable with quantitative methods, thus amenable to high throughput testing. Here we describe and demonstrate the use of a novel 3D microfluidic blood brain niche (&#181;mBBN) platform where multiple elements of the niche can be cultured for an extended period (several days), fluorescently imaged by confocal microscopy, and the images reconstructed using an innovative confocal tomography technique; all aimed to understand the development of micro-metastasis and changes to the tumor micro-environment (TME) in a repeatable and quantitative manner. We demonstrate how to fabricate, seed, image, and analyze the cancer cells and TME cellular and humoral components, using this platform. Moreover, we show how artificial intelligence (AI) is used to identify the intrinsic phenotypic differences of cancer cells that are capable of transit through a model &#181;mBBN and to assign them an objective index of brain metastatic potential. The data sets generated by this method can be used to answer basic and translational questions about metastasis, the efficacy of therapeutic strategies, and the role of the TME in both.

Here, we present a protocol for preparing and culturing a blood brain barrier metastatic tumor micro-environment and then quantifying its state using confocal imaging and artificial intelligence (machine learning).

Brain metastases are the most lethal cancer lesions; 10-30% of all cancers metastasize to the brain, with a median survival of only ~5-20 months, ...

An Ex Vivo Brain Slice Model to Study and Target Breast Cancer Brain Metastatic Tumor Growth

Brain metastasis is a serious consequence of breast cancer for women as these tumors are difficult to treat and are associated with poor clinical outcomes. Preclinical mouse models of breast cancer brain metastatic (BCBM) growth are useful but are expensive, and it is difficult to track live cells and tumor cell invasion within the brain parenchyma. Presented here is a protocol for ex vivo brain slice cultures from xenografted mice containing intracranially injected breast cancer brain-seeking clonal sublines. MDA-MB-231BR luciferase tagged cells were injected intracranially into the brains of Nu/Nu female mice, and following tumor formation, the brains were isolated, sliced, and cultured ex vivo. The tumor slices were imaged to identify tumor cells expressing luciferase and monitor their proliferation and invasion in the brain parenchyma for up to 10 days. Further, the protocol describes the use of time-lapse microscopy to image the growth and invasive behavior of the tumor cells following treatment with ionizing radiation or chemotherapy. The response of tumor cells to treatments can be visualized by live-imaging microscopy, measuring bioluminescence intensity, and performing histology on the brain slice containing BCBM cells. Thus, this ex vivo slice model may be a useful platform for rapid testing of novel therapeutic agents alone or in combination with radiation to identify drugs personalized to target an individual patient&#39;s breast cancer brain metastatic growth within the brain microenvironment.

An Ex Vivo Brain Slice Model to Study and Target Breast Cancer Brain Metastatic Tumor Growth

We introduce a protocol for measuring real-time drug and radiation response of breast cancer brain metastatic cells in an organotypic brain slice model. The methods provide a quantitative assay to investigate the therapeutic effects of various treatments on brain metastases from breast cancer in an ex vivo manner within the brain microenvironment interface.

Brain metastasis is a serious consequence of breast cancer for women as these tumors are difficult to treat and are associated with poor clinical ...

Monitoring Breast Cancer Growth and Metastatic Colony Formation in Mice using Bioluminescence

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several animal models have been generated, including the widely used orthotopic mouse models, where cancer cells are injected into the mammary fat pad. However, these models cannot help monitor tumor growth kinetics and metastatic colonization. Cutting-edge tools to monitor cancer cells in real time in mice will significantly advance the understanding of tumor biology. 
Here, breast cancer cell lines stably expressing luciferase and green fluorescent protein (GFP) were established. Specifically, this technique contains two sequential steps initiated by measuring the luciferase activity in vitro and followed by the implantation of the cancer cells into mammary fat pads of nonobese diabetic-severe combined immunodeficiency (NOD-SCID) mice. After the injection, both the tumor growth and metastatic colonization are monitored in real time by the noninvasive bioluminescence imaging system. Then, the quantification of GFP-expressing metastases in the lungs will be examined by fluorescence microscopy to validate the observed bioluminescence results. This sophisticated system combining luciferase and fluorescence-based detection tools evaluates cancer metastasis in vivo, which has great potential for use in breast cancer therapeutics and disease management.

Here, we describe a noninvasive monitoring method involving luciferase and green fluorescent protein expression in various breast cancer cell lines. This protocol provides a technique to monitor tumor formation and metastatic colonization in real time in mice.

Breast cancer is a frequent heterogeneous malignancy and the second leading cause of mortality in women, mainly due to distant organ metastasis. Several ...